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*   Copyright (c) 2010, Pierre Favier
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using System;
using System.Threading;
using NTasking.ValidationTests.ACATS_3_0.Support;
using NUnit.Framework;
using Rhino.Mocks;

namespace NTasking.ValidationTests.ACATS_3_0.C9
{

    [TestFixture(Description = "")]
    public class C9740003 : ValidationTest
    {

        private static int TC_Count = 1234;
        private static bool TC_TriggeringStatementCompleted = false;


        internal class TransactioCancelled : Exception {}


        internal enum KeyEnum
        {
            None,
            Cancel,
            Deposit,
            Withdraw
        }


        internal class ATMKeybordTask : Task
        {

            [Entry]
            internal Action CancelPressed { get; private set; }


            protected override void Body()
            {
                KeyEnum keyPressed = KeyEnum.None;
                bool exit = false;

                while (!exit)
                {
                    // Force entry calls to be quened then set guard to true
                    keyPressed = ListenForInput();

                    KeyEnum pressed = keyPressed;
                    Select(s => s.
                        When(() => pressed == KeyEnum.Cancel).
                            Accept(CancelPressed, () =>
                            {
                                TC_TriggeringStatementCompleted = true;
                            }).
                            // User has cancelled the transaction so we exit the
                            // loop and allow the task to terminate
                            Then(() => exit = true).
                        Else(() =>
                        {
                            keyPressed = KeyEnum.None;
                        }));
                }
            }


            private KeyEnum ListenForInput()
            {
                KeyEnum result = KeyEnum.None;

                // Model the situation where the user waits a bit for the card to
                // be validated, then presses cancel before it completes.
                
                // Delay long enough to force queuing of Keyboard.Cancel_Pressed.
                Ada.Delay(Impdef.MinimumTaskSwitch);

                if (Equal(3, 3)) // Always true
                    result = KeyEnum.Cancel;

                return result;
            }

        }


        internal class ATMCardType
        {
            public int Number { get; set; }
            public int Pin { get; set; }
        }


        private static bool Equal(int left, int right)
        {
            return left == right;
        }


        private static void ReadCard(ATMCardType card)
        {
            card.Number = 9999;
            card.Pin = 111;
        }


        private static void ValidateCard(ATMCardType card)
        {
            // Simulate an exceedingly long validation activity.
            while (true)
            {
                TC_Count = (TC_Count + 1)%card.Pin;
                // Synch. point to allow transfer of control to Keyboard
                // task during this simulation
                Ada.Delay(Impdef.MinimumTaskSwitch);
                if (!Equal(TC_Count, TC_Count)) // Always false
                    break;
            }
        }


        private static void PerformTransaction(ATMCardType card, IValidationTestResult result)
        {
            // Triggering alternative sequence of statements
            // not executed
            result.TestFailed();

            if (!TC_TriggeringStatementCompleted)
                // Triggering statement did not complete
                result.TestFailed();

            if (TC_Count == 1234)
                // Abortable part did not execute
                result.TestFailed();
        }


        [Test(Description =
            "Check that the abortable part of an asynchronous select statement" +
            "is aborted if it does not complete before the triggering statement" +
            "completes, where the triggering statement is a  task entry call, and" +
            "the entry call is queued." +
            "\n" +
            "Check that the sequence of statements of the triggering alternative" +
            "is executed after the abortable part is left.")]
        public void Test()
        {
            IValidationTestResult result = Mocks.DynamicMock<IValidationTestResult>();

            ATMKeybordTask keyboard = null;
            ATMCardType card = new ATMCardType();

            ReadCard(card);

            Ada.Declare(() =>
            {
                keyboard = new ATMKeybordTask();

                // Setup test expectations

                Expect.Call(result.TestFailed).Repeat.Never();

                Mocks.ReplayAll();
            },
            Begin: () =>
            {
                // Start test execution

                //
                // Asynchronous select is tested here
                //

                Ada.Select(s =>
                    // Entry call is initially queued, so
                    // abortable part starts.
                    s.Call(keyboard.CancelPressed)().
                    // This is executed after ValidateCard
                    // is aborted.
                    Then(() =>
                    {
                        throw new TransactioCancelled();
                    }).
                ThenAbort(() =>
                {
                    // Keyboard.Cancel_Pressed is accepted
                    // and completes before this call
                    // finishes; it is then aborted.
                    ValidateCard(card);
                    // Check that the whole of the abortable part is aborted, not
                    // just the statement in the abortable part that was executing
                    // at the time
                    result.TestFailed();
                }));

                // Should not be reached.
                PerformTransaction(card, result);
            },
            Exception: (ex) =>
            {
                if (ex is TransactioCancelled)
                {
                    if (!TC_TriggeringStatementCompleted)
                        // Triggering alternative sequence of statements
                        // executed but triggering statement not complete
                        result.TestFailed();

                    if (TC_Count == 1234)
                        // Abortable part did not execute
                        result.TestFailed();

                    return false;
                }

                return true;
            });

        }

    }

}
